Clean up unix/native/common/sun/awt

This is from a code review following the jigsaw source file restructuring:

* The directory ./unix/native/common/sun/awt contains five more or less unrelated .c files. Three of them are only used in libawt_xawt, and should be moved there:
  ./unix/native/common/sun/awt/awt_Font.c
  ./unix/native/common/sun/awt/fontpath.c
  ./unix/native/common/sun/awt/X11Color.c
Of the remaining two CUPSfuncs.c seems correctly placed, since it is shared between libawt_xawt and libawt_lwawt. However, I'm wondering about initIDs.c. It is compiled in libawt as well as libawt_xawt, but when I checked some random functions, they are exported (via the mapfile) for libawt only. So I believe it is a mistake to include it in libawt_xawt, and that it should be moved to the libawt directory. This will need verification from someone on the AWT team.